Cruise control systems make it possible to set the vehicle's speed to a desired level selected by the driver, or, if a vehicle whose speed is lower than this desired speed is detected traveling ahead, to automatically maintain an adequate safety distance to the vehicle ahead.
While most conventional cruise control systems of this type, which are also referred to as ACC (Adaptive Cruise Control) systems, are only activatable above a determined minimum speed of, for example, 40 km/h, German Published Patent Application No. 199 58 520 describes a cruise control system also having a stop function which allows the vehicle to be automatically braked to a standstill, e.g., when approaching the tail end of a traffic jam. Within the scope of a stop-and-go function, automatic drive-off is possible under certain conditions when the vehicle ahead starts moving again.
The ACC function, as well as the stop-and-go function may generally be activated or deactivated by the driver via push-button control. If a vehicle having an automatic transmission is braked to a standstill using the stop-and-go function, the controller holds the vehicle brake automatically applied to prevent the vehicle to roll again. If the controller is inactivated by a driver's command, this results in the brake being released and the vehicle rolling again. If the driver has not foreseen this consequence, critical situations or irritations of the driver may result.